i found an alternative to the CAT hydraulic o-ring at the local Pep Boys Auto Parts shop.....
the register receipt says:
O-RINGS
0-37495-64320
for a couple of bucks you get a ziplock bag of 3 o-rings with the following dimensions:
width 3/16inch
i.d. 1-1/8inch
o.d. 1-1/2inch
it takes some getting used to and how well they work depends on how the bar-end and grip mesh. trial and error conquers all.
henry